21 May 1999. Thanks to MS.

Date: Fri, 21 May 1999 10:36:39 -0600
From: Mike Stay <staym@accessdata.com>
To: coderpunks@toad.com
Cc: cryptography@c2.net
Subject: quantum codebreaker

There is a paper just published today on the Los Alamos Nat'l Labs
preprint site:

   http://xxx.lanl.gov/abs/quant-ph/9905064

on how to simulate arbitrary nonlinear quantum dynamics.  They give 
examples of existing systems where the effect has already been seen 
and then give a general description of using feedback to make a quantum 
system behave nonlinearly. They show that in such systems, distances 
between quantum states are NOT preserved.

It was previously published hat if QM was nonlinear at all, one could 
do a quantum search in log N time instead of sqrt N time. 

   http://xxx.lanl.gov/abs/quant-ph/9801041

   http://xxx.lanl.gov/abs/quant-ph/9804025

If today's paper is correct, then it's just a matter of sufficient
technology to break ANY code with a known-plaintext attack.
-- 
Mike Stay
Cryptographer / Programmer
AccessData Corp.

mailto:staym@accessdata.com